JP4677533B2 - Lens drive device - Google Patents

Description

  The present invention relates to a lens driving device used for a portable small camera or the like.

  Japanese Patent Application Laid-Open No. 2004-26883 discloses a lens drive in which a front spring and a rear spring are attached to a lens support body before and after the optical axis direction, and the lens support body is moved in the optical axis direction of the lens by electromagnetic force generated by energizing a coil. An apparatus is disclosed.

  As shown in FIG. 5, the conventional front spring and rear spring (only one is shown because it is substantially the same shape) 51 are each formed in an annular shape, and an inner peripheral end (inner ring) 53. And an outer peripheral end (outer ring) 55 are connected by an arm portion 57 provided between them along the circumferential direction. A connecting portion (inner peripheral side connecting portion) 59 between the inner peripheral side end portion 53 and the arm portion 57 and a connecting portion (outer peripheral side connecting portion) 61 between the outer peripheral side end portion 55 and the arm portion 57 are respectively in the radial direction. It protrudes to.

JP 2004-280031 A

  However, in each spring 51 of Patent Document 1, when the stress in the circumferential direction, the radial direction, or the torsional direction acts, the arm portion 57 and the connecting portions 59 and 61 are easily or locally susceptible to the stress. The part 57 and the connecting parts 59 and 61 may be deformed or damaged.

  In particular, in a lens driving device used for a portable small camera or the like, a small camera is often carried around in a pocket or back, so that the lens driving device is shaken or shocked when the small camera is carried (when not in use). These swings and impacts may act on the front and rear springs as stress in the circumferential direction, radial direction, and twist direction.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a lens driving device that is excellent in shaking and impact resistance by reducing stress in various directions acting on the front and rear springs.

According to the first aspect of the present invention, there is provided a base, a lens support, a magnet and a coil arranged concentrically, one of which is a base and the other attached to the lens support, and at least an inner peripheral end. The front spring and the rear spring are attached to the support and attached to the base at the outer peripheral end, and the front spring and the rear spring are attached to the lens support in the front and rear directions in the optical axis direction of the lens, respectively. A lens driving device that moves the lens support in the optical axis direction of the lens by electromagnetic force generated by energization,
Each of the front spring and the rear spring is an annular leaf spring in plan view, the inner peripheral end has an annular shape, and the outer peripheral end has an annular shape with a larger radius than the inner peripheral end. The arm portion is provided between the inner peripheral side end portion and the outer peripheral side end portion, and the arm portion has a plurality of peripheral portions provided along the circumferential direction of the spring with different diameters from each other, It has a connecting portion with the side end portion and a connecting portion with the outer peripheral side end portion, and the plurality of peripheral portions are connected by connecting the end portions with curved connecting portions, and are connected to the inner peripheral side end portion. The connecting portion and the connecting portion between the outer peripheral side end portions are located at positions shifted from each other in the circumferential direction of the spring, and each connecting portion has a curved shape protruding in the radial direction.

  The invention described in claim 2 is characterized in that, in the invention described in claim 1, the arm portion and each connecting portion have substantially the same width.

  According to the first aspect of the present invention, in the arm portion, the plurality of peripheral portions having different radii are connected by the arc-shaped connecting portion and are continuous, so that the connecting portion with the inner peripheral side end portion (hereinafter, “ The inner peripheral side connecting portion) and the outer peripheral side end portion (hereinafter referred to as the "outer peripheral side connecting portion"), which are curved in response to stress in the radial direction, the peripheral direction and the torsional direction. The connecting portion is elastically deformed to reduce stress in these directions. On the other hand, the inner and outer connection portions are also formed in a curved shape when subjected to stress in the radial direction, the peripheral direction, and the torsional direction, so that each connection portion is easily elastically deformed. Reduce stress in each direction.

  In addition, since the arm portion, the inner peripheral side connecting portion, and the outer peripheral side connecting portion are easily elastically deformed with respect to the stress in each direction, the stress acting on each portion can be integrally reduced.

  Since the connecting part of the arm part, the inner peripheral side connecting part, and the outer peripheral side connecting part are each formed in a curved shape, the configuration is simple, and it can be manufactured by the same shape-cutting as the conventional one.

  Furthermore, the urging force in the optical axis direction acting on the lens support which is originally required for the front spring and the rear spring is not impaired.

  According to invention of Claim 2, while being able to obtain the effect of Claim 1, it can disperse | distribute stress substantially equally to the connection part of an arm part, an inner side connection part, and an outer side connection part, Local concentration can be prevented.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a plan view of the front spring and the rear spring shown in FIG. 2, FIG. 2 is an exploded perspective view of the lens driving device according to the present embodiment, and FIG. 3 is a lens driving device according to the present embodiment. FIG. 4 is a longitudinal sectional view showing a state where the lens driving device shown in FIG. 3 is driven.

  A lens driving device 1 according to the present embodiment is a lens driving device for an autofocus camera incorporated in a mobile phone.

The lens driving device 1 includes a substantially cylindrical yoke 3, a base 5 on which the yoke 3 is mounted, a lens support 7 disposed on the inner peripheral side of the yoke 3, and a front spring attached to the lens support 7. 9 and a rear spring 11. The front spring 9 is arranged on the front side (one side) of the lens support 7 in the optical axis direction of the lens, and the rear spring 11 is rear side in the optical axis direction of the lens (the other side). ).
The yoke 3 has a substantially U-shaped cross section, and a magnet 13 is disposed inside the U-shape, and a coil 15 is disposed on the inner peripheral side of the magnet inside the U-shape. The magnet 13 is fixed to the base 5 via a rear spacer 17. The coil 15 is fixed to the outer peripheral portion 7a of the lens support 7 and the outer peripheral portion 7a of the lens support 7 enters the inside of the yoke 3. The outer peripheral portion 7a of the lens support 7 is formed by a U-shape. The gap between the yokes 3 is moved.

  The base 5 has an outer peripheral wall 5 a positioned along the outer peripheral surface of the yoke 3, and a base portion 5 b positioned on the rear side of the yoke 3 (the rear side in the optical axis direction of the lens). A yoke 3 is fixed on the circumferential side. Further, an outer peripheral end portion 11 b of the rear spring 11 is fixed between the base portion 5 b and the rear spacer 17. A sensor holder 19 is attached to the base 5 b of the base 5.

  The lens support 7 has a substantially cylindrical shape, in which a lens 20 is housed, and is attached to the inner peripheral side of the yoke 3 so as to be movable along the optical axis.

  The front spring 9 is a substantially annular leaf spring in plan view, and is provided with an inner peripheral end 9a and an outer peripheral end 9b. The inner peripheral side end portion 9a has an annular shape, and the outer peripheral side end portion 9b has an annular shape with a larger radius than the inner peripheral side end portion, and is located between the inner peripheral side end portion 9a and the outer peripheral side end portion 9b. Is provided with an arm portion 25. The inner peripheral end 9a is clamped and fixed between the lens support 7 and the cap 24, and the outer peripheral end 9b is clamped and fixed between the yoke 3 fixed to the base 5 and the frame 23. A front spacer 21 is interposed between the outer peripheral end 9b and the yoke 3.

  The rear spring 11 is substantially the same shape as the front spring 9 and is a substantially annular leaf spring in plan view. The inner peripheral end portion 11a has an annular shape, and the outer peripheral end portion 11b has an annular shape with a larger radius than the inner peripheral end portion 11a, and the inner peripheral end portion 11a and the outer peripheral end portion 11b. Between the two, an arm portion 25 is provided. The inner peripheral end 11 a of the rear spring 11 is fixed to the rear end of the lens support 7, and the outer peripheral end 9 b is fixed between the base portion 5 b of the base 5 and the rear spacer 17.

  Each of the front spring 9 and the rear spring 11 is flat in a natural state (a state in which no load is applied) before assembly.

  Here, the configurations of the front spring 9 and the rear spring 11 will be described in more detail. However, since the configurations of the front spring 9 and the rear spring 11 are substantially the same, the front spring 9 will be described and the configuration of the rear spring 11 will be described. Is omitted.

  The front spring 9 is provided with three arm portions 25 between the inner peripheral end portion 9a and the outer peripheral end portion 9b, and each arm portion 25 has an inner peripheral end portion 9a and an outer peripheral end portion. 9b. Each arm portion 25 is provided along the circumferential direction, and an insertion space 27 for the projection 7b (see FIG. 4) of the lens support 7 is provided between the adjacent arm portions 25, 25. The protrusion 7 b of the lens support 7 can be brought into contact with the base portion 5 b of the base 5 through the insertion space 27.

  Each arm portion 25 has three peripheral portions 25 a, 25 b, 25 c provided in the circumferential direction with different diameters, an inner peripheral side connecting portion 28, and an outer peripheral side connecting portion 30. Each of the peripheral portions 11a, 11b, and 11c is connected continuously by connecting portions 31 having curved ends (in this embodiment, a semicircular arc shape).

  The inner peripheral side connecting portion 28 has an arc shape that forms approximately 3/4 of a ring projecting radially outward from the inner peripheral side end portion 9a, and the arm portion 25 is connected to the arc-shaped end portion. . The outer peripheral side connecting portion 30 has an arc shape projecting radially inward from the outer end portion 9b, and has an arc shape that forms approximately 3/4 of an annular shape, and the arm portion 25 is connected to the arc-shaped end portion. ing.

  Each arm part 25, the inner periphery side connection part 28, and the outer periphery side connection part 30 are each formed in substantially the same width.

Next, assembly, operation, and effect of the lens driving device 1 according to the present invention will be described.
Assembling is performed by attaching the inner peripheral end 11 a of the rear spring 11 to the lens support 7, and arranging the magnet 13 and the coil 15 fixed to the lens support 7 inside the yoke 3. It is assembled to the part 5 b via the rear spacer 17. Incidentally, the projection 7 b of the lens support 7 is inserted into the insertion space 27 of the rear spring 11. Thereafter, the inner peripheral side end 9 a of the front spring 9 is placed between the front spacer 21 and the yoke 3 and fixed with the cap 24, and the frame 23 is attached to the base 5 and the outer peripheral side end 9 b of the front spring 9. Is fixed by the frame 23.

  The front side spring 9 and the rear side spring 11 are manufactured by cutting the same shape as in the prior art.

  In this assembled state, since the lens support 7 is supported by the two springs 9 and 11, even if a shake or an impact occurs, the lens support 7 is unlikely to be shaken or rattled, and the impact resistance is improved. Excellent.

  In each arm portion 25 of the front spring 9 and the rear spring 11, a plurality of peripheral portions 25 a, 25 b, 25 c having different radii are continuously connected by an arc-shaped connecting portion 31. The curved connecting portion 31 is elastically deformed to reduce stress in various directions against radial stress acting on the outer peripheral side connecting portion 30, stress in the peripheral direction, and stress in the torsional direction. be able to. Further, in the inner peripheral side connecting portion 28 and the outer peripheral side connecting portion 30, each of the connecting portions 28 and 30 formed in an arc shape is elastically deformed when subjected to stress in the radial direction, stress in the peripheral direction, and stress in the torsional direction. To reduce stress in each direction. In particular, since the inner peripheral side connecting portion 28 and the outer peripheral side connecting portion 30 are each formed in an arc shape that is 1/2 or more of a circle, they are easily elastically deformed and easily absorb stress.

  In the present embodiment, the connecting portion 31, the inner peripheral side connecting portion 28, and the outer peripheral side connecting portion 30 are formed in an arc shape. ) Can be elastically deformed to reduce the stress in each direction and prevent local stress concentration.

  In particular, since the arm portion 25, the inner peripheral side connecting portion 28, and the outer peripheral side connecting portion 30 have substantially the same width, stress can be distributed to these portions substantially evenly, and stress can be prevented from being concentrated locally. .

  Therefore, damage and breakage of the front spring 9 and the rear spring 11 can be prevented when a small camera or mobile phone equipped with the lens driving device according to the present embodiment is shaken or shocked when it is carried. It is possible to provide an excellent lens driving device.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

  For example, the magnet 13 may be fixed to the lens support 7, the coil 15 may be fixed to the base 5, and the lens support may be driven in the optical axis direction by excitation of the coil.

  The connection part 31, the inner peripheral side connection part 28, and the outer peripheral side connection part 30 are not limited to being formed in an arc shape, but may be curved.

FIG. 3 is a plan view of a front spring and a rear spring shown in FIG. 2. It is a disassembled perspective view of the lens drive device concerning this Embodiment. It is a longitudinal cross-sectional view of the lens drive device concerning this Embodiment. It is a longitudinal cross-sectional view which shows the state which the lens drive device of FIG. 3 driven. It is a top view of the front side spring and the rear side spring concerning a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens drive device 3 Yoke 5 Base 7 Lens support body 9 Front side spring 9a Inner peripheral side edge part 9b Outer peripheral side edge part 11 Rear side spring 11a Inner peripheral side edge part 11b Outer peripheral side end part 13 Magnet 15 Coil 25 Arm part 25a, 25b, 25c Peripheral portion 28 Inner peripheral side connecting portion 30 Outer peripheral side connecting portion 31 Connecting portion

Claims (2)

A base, a lens support, a magnet and a coil arranged concentrically, one of which is the base and the other attached to the lens support, and at least the inner peripheral end attached to the lens support, the outer peripheral end The front and rear springs are attached to the base. The front and rear springs are attached to the lens support body in the front and rear directions in the optical axis direction of the lens, and support the lens by electromagnetic force generated by energizing the coil. A lens driving device for moving the body in the direction of the optical axis of the lens,
Each of the front spring and the rear spring is an annular leaf spring in plan view, the inner peripheral end has an annular shape, and the outer peripheral end has an annular shape with a larger radius than the inner peripheral end. The arm portion is provided between the inner peripheral side end portion and the outer peripheral side end portion, and the arm portion has a plurality of peripheral portions provided along the circumferential direction of the spring with different diameters from each other, It has a connecting portion with the side end portion and a connecting portion with the outer peripheral side end portion, and the plurality of peripheral portions are connected by connecting the end portions with curved connecting portions, and are connected to the inner peripheral side end portion. The lens driving device according to claim 1 , wherein the connecting portion and the connecting portion between the outer peripheral side end portions are shifted from each other in the circumferential direction of the spring, and each connecting portion has a curved shape protruding in the radial direction.
The lens driving device according to claim 1, wherein the arm portion and each connecting portion have substantially the same width.

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